More particularly, the invention relates to an antivibration support of this type, comprising first and second rigid strength members suitable for securing to respective ones of the two rigid elements to be united, and an elastomer body having a thick wall interconnecting the two rigid strength members and partially defining a working chamber, said thick wall being substantially bell-shaped, extending along the main vibration direction between a peripheral base secured to the second strength member and a crown secured to the first strength member, said elastomer base further including a freely-deformable thin wall which is integrally formed with the above-mentioned thick wall and which partially defines a compensation chamber that is in communication with the working chamber via a narrow channel, the two chambers and the narrow channel being filled with a liquid, the second strength member being a base plate which extends in a plane that is substantially perpendicular to the main vibration direction and which has a "support" face secured in sealed manner with the elastomer body to co-operate therewith in defining the two chambers and the narrow channel.
Such a device is described in document EP-A-0 236 199, for example.
However, the device described in that document does not include a decoupling flap valve between the two rigid strength members for filtering small amplitude vibrations of relatively high frequency.